1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * ebt_log |
4 | * |
5 | * Authors: |
6 | * Bart De Schuymer <bdschuym@pandora.be> |
7 | * Harald Welte <laforge@netfilter.org> |
8 | * |
9 | * April, 2002 |
10 | * |
11 | */ |
12 | #include <linux/module.h> |
13 | #include <linux/ip.h> |
14 | #include <linux/in.h> |
15 | #include <linux/if_arp.h> |
16 | #include <linux/spinlock.h> |
17 | #include <net/netfilter/nf_log.h> |
18 | #include <linux/ipv6.h> |
19 | #include <net/ipv6.h> |
20 | #include <linux/in6.h> |
21 | #include <linux/netfilter/x_tables.h> |
22 | #include <linux/netfilter_bridge/ebtables.h> |
23 | #include <linux/netfilter_bridge/ebt_log.h> |
24 | #include <linux/netfilter.h> |
25 | |
26 | static DEFINE_SPINLOCK(ebt_log_lock); |
27 | |
28 | static int ebt_log_tg_check(const struct xt_tgchk_param *par) |
29 | { |
30 | struct ebt_log_info *info = par->targinfo; |
31 | |
32 | if (info->bitmask & ~EBT_LOG_MASK) |
33 | return -EINVAL; |
34 | if (info->loglevel >= 8) |
35 | return -EINVAL; |
36 | info->prefix[EBT_LOG_PREFIX_SIZE - 1] = '\0'; |
37 | return 0; |
38 | } |
39 | |
40 | struct tcpudphdr { |
41 | __be16 src; |
42 | __be16 dst; |
43 | }; |
44 | |
45 | struct arppayload { |
46 | unsigned char mac_src[ETH_ALEN]; |
47 | unsigned char ip_src[4]; |
48 | unsigned char mac_dst[ETH_ALEN]; |
49 | unsigned char ip_dst[4]; |
50 | }; |
51 | |
52 | static void |
53 | print_ports(const struct sk_buff *skb, uint8_t protocol, int offset) |
54 | { |
55 | if (protocol == IPPROTO_TCP || |
56 | protocol == IPPROTO_UDP || |
57 | protocol == IPPROTO_UDPLITE || |
58 | protocol == IPPROTO_SCTP || |
59 | protocol == IPPROTO_DCCP) { |
60 | const struct tcpudphdr *pptr; |
61 | struct tcpudphdr _ports; |
62 | |
63 | pptr = skb_header_pointer(skb, offset, |
64 | len: sizeof(_ports), buffer: &_ports); |
65 | if (pptr == NULL) { |
66 | pr_cont(" INCOMPLETE TCP/UDP header" ); |
67 | return; |
68 | } |
69 | pr_cont(" SPT=%u DPT=%u" , ntohs(pptr->src), ntohs(pptr->dst)); |
70 | } |
71 | } |
72 | |
73 | static void |
74 | ebt_log_packet(struct net *net, u_int8_t pf, unsigned int hooknum, |
75 | const struct sk_buff *skb, const struct net_device *in, |
76 | const struct net_device *out, const struct nf_loginfo *loginfo, |
77 | const char *prefix) |
78 | { |
79 | unsigned int bitmask; |
80 | |
81 | /* FIXME: Disabled from containers until syslog ns is supported */ |
82 | if (!net_eq(net1: net, net2: &init_net) && !sysctl_nf_log_all_netns) |
83 | return; |
84 | |
85 | spin_lock_bh(lock: &ebt_log_lock); |
86 | printk(KERN_SOH "%c%s IN=%s OUT=%s MAC source = %pM MAC dest = %pM proto = 0x%04x" , |
87 | '0' + loginfo->u.log.level, prefix, |
88 | in ? in->name : "" , out ? out->name : "" , |
89 | eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest, |
90 | ntohs(eth_hdr(skb)->h_proto)); |
91 | |
92 | if (loginfo->type == NF_LOG_TYPE_LOG) |
93 | bitmask = loginfo->u.log.logflags; |
94 | else |
95 | bitmask = NF_LOG_DEFAULT_MASK; |
96 | |
97 | if ((bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto == |
98 | htons(ETH_P_IP)) { |
99 | const struct iphdr *ih; |
100 | struct iphdr _iph; |
101 | |
102 | ih = skb_header_pointer(skb, offset: 0, len: sizeof(_iph), buffer: &_iph); |
103 | if (ih == NULL) { |
104 | pr_cont(" INCOMPLETE IP header" ); |
105 | goto out; |
106 | } |
107 | pr_cont(" IP SRC=%pI4 IP DST=%pI4, IP tos=0x%02X, IP proto=%d" , |
108 | &ih->saddr, &ih->daddr, ih->tos, ih->protocol); |
109 | print_ports(skb, protocol: ih->protocol, offset: ih->ihl*4); |
110 | goto out; |
111 | } |
112 | |
113 | #if IS_ENABLED(CONFIG_BRIDGE_EBT_IP6) |
114 | if ((bitmask & EBT_LOG_IP6) && eth_hdr(skb)->h_proto == |
115 | htons(ETH_P_IPV6)) { |
116 | const struct ipv6hdr *ih; |
117 | struct ipv6hdr _iph; |
118 | uint8_t nexthdr; |
119 | __be16 frag_off; |
120 | int offset_ph; |
121 | |
122 | ih = skb_header_pointer(skb, offset: 0, len: sizeof(_iph), buffer: &_iph); |
123 | if (ih == NULL) { |
124 | pr_cont(" INCOMPLETE IPv6 header" ); |
125 | goto out; |
126 | } |
127 | pr_cont(" IPv6 SRC=%pI6 IPv6 DST=%pI6, IPv6 priority=0x%01X, Next Header=%d" , |
128 | &ih->saddr, &ih->daddr, ih->priority, ih->nexthdr); |
129 | nexthdr = ih->nexthdr; |
130 | offset_ph = ipv6_skip_exthdr(skb, start: sizeof(_iph), nexthdrp: &nexthdr, frag_offp: &frag_off); |
131 | if (offset_ph == -1) |
132 | goto out; |
133 | print_ports(skb, protocol: nexthdr, offset: offset_ph); |
134 | goto out; |
135 | } |
136 | #endif |
137 | |
138 | if ((bitmask & EBT_LOG_ARP) && |
139 | ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) || |
140 | (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) { |
141 | const struct arphdr *ah; |
142 | struct arphdr _arph; |
143 | |
144 | ah = skb_header_pointer(skb, offset: 0, len: sizeof(_arph), buffer: &_arph); |
145 | if (ah == NULL) { |
146 | pr_cont(" INCOMPLETE ARP header" ); |
147 | goto out; |
148 | } |
149 | pr_cont(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d" , |
150 | ntohs(ah->ar_hrd), ntohs(ah->ar_pro), |
151 | ntohs(ah->ar_op)); |
152 | |
153 | /* If it's for Ethernet and the lengths are OK, |
154 | * then log the ARP payload |
155 | */ |
156 | if (ah->ar_hrd == htons(1) && |
157 | ah->ar_hln == ETH_ALEN && |
158 | ah->ar_pln == sizeof(__be32)) { |
159 | const struct arppayload *ap; |
160 | struct arppayload _arpp; |
161 | |
162 | ap = skb_header_pointer(skb, offset: sizeof(_arph), |
163 | len: sizeof(_arpp), buffer: &_arpp); |
164 | if (ap == NULL) { |
165 | pr_cont(" INCOMPLETE ARP payload" ); |
166 | goto out; |
167 | } |
168 | pr_cont(" ARP MAC SRC=%pM ARP IP SRC=%pI4 ARP MAC DST=%pM ARP IP DST=%pI4" , |
169 | ap->mac_src, ap->ip_src, |
170 | ap->mac_dst, ap->ip_dst); |
171 | } |
172 | } |
173 | out: |
174 | pr_cont("\n" ); |
175 | spin_unlock_bh(lock: &ebt_log_lock); |
176 | } |
177 | |
178 | static unsigned int |
179 | ebt_log_tg(struct sk_buff *skb, const struct xt_action_param *par) |
180 | { |
181 | const struct ebt_log_info *info = par->targinfo; |
182 | struct nf_loginfo li; |
183 | struct net *net = xt_net(par); |
184 | |
185 | li.type = NF_LOG_TYPE_LOG; |
186 | li.u.log.level = info->loglevel; |
187 | li.u.log.logflags = info->bitmask; |
188 | |
189 | /* Remember that we have to use ebt_log_packet() not to break backward |
190 | * compatibility. We cannot use the default bridge packet logger via |
191 | * nf_log_packet() with NFT_LOG_TYPE_LOG here. --Pablo |
192 | */ |
193 | if (info->bitmask & EBT_LOG_NFLOG) |
194 | nf_log_packet(net, pf: NFPROTO_BRIDGE, hooknum: xt_hooknum(par), skb, |
195 | in: xt_in(par), out: xt_out(par), li: &li, fmt: "%s" , |
196 | info->prefix); |
197 | else |
198 | ebt_log_packet(net, pf: NFPROTO_BRIDGE, hooknum: xt_hooknum(par), skb, |
199 | in: xt_in(par), out: xt_out(par), loginfo: &li, prefix: info->prefix); |
200 | return EBT_CONTINUE; |
201 | } |
202 | |
203 | static struct xt_target ebt_log_tg_reg __read_mostly = { |
204 | .name = "log" , |
205 | .revision = 0, |
206 | .family = NFPROTO_BRIDGE, |
207 | .target = ebt_log_tg, |
208 | .checkentry = ebt_log_tg_check, |
209 | .targetsize = sizeof(struct ebt_log_info), |
210 | .me = THIS_MODULE, |
211 | }; |
212 | |
213 | static int __init ebt_log_init(void) |
214 | { |
215 | return xt_register_target(target: &ebt_log_tg_reg); |
216 | } |
217 | |
218 | static void __exit ebt_log_fini(void) |
219 | { |
220 | xt_unregister_target(target: &ebt_log_tg_reg); |
221 | } |
222 | |
223 | module_init(ebt_log_init); |
224 | module_exit(ebt_log_fini); |
225 | MODULE_DESCRIPTION("Ebtables: Packet logging to syslog" ); |
226 | MODULE_LICENSE("GPL" ); |
227 | |